Fitting images to a page

Sorry if this is a dumb question, just started my trial.

When I insert images into a page, they display fine and I can resize them. But when I compile, it doesn’t size the image to fit the page but cuts off a big chunk of the image.

I’m going to have a lot of images (reference book), but I don’t want to resize hundreds of images just to do a different page size.

Tried it both on and the latest beta.

Great software… love the concept and user experience. Just need the images to work or it’s a deal breaker. Thanks.